Banned drugs found in 3,800 samples

Banned substances were found in more than 3,800 samples out of 283,304 tests carried out worldwide last year, World Anti-Doping Agency figures reveal.

However, that represented a fall, across all sports, of more than 10%,despite an increase in the number of tests carried out.

Athletics has been the subject of allegations of widespread doping.

And Wada has told the BBC more than 10% of elite athletes could be using performance-enhancing drugs.

August's athletics World Championships in Beijing included 66 competitors who had previously been subject to doping sanctions.

Athletics' governing body, the International Association of Athletics Federations (IAAF), carried out more than 1,400 tests on an estimated 600-700 athletes - only a third of the total number of competitors - in China. Just two - Kenyan runners Joyce Zakary and Koki Manunga - failed them, although the IAAF said samples would be frozen and stored for future reanalysis as science and technology progressed.

As well as the reduction in samples containing banned substances - or 'adverse analytical findings' - in 2014, the number of tests requiring further investigation also fell. In contrast, the number of adverse findings had increased by more than 10% between 2012 and 2013